Study finds small mammals aid expansion of warm-climate trees

A new study by Alessio Mortelliti, an assistant professor of wildlife habitat ecology at the University of Maine, finds small mammals could affect whether trees spread to new areas in a warming climate.

Mortelliti’s research, which was published in the journal Oikos, looks at the behavior of small forest mammals that eat acorns and other tree seeds. 

By choosing certain seeds and rejecting others, the animals can alter the trees that make up a forest, according to a Second Century Stewardship news release. 

If they eat all the seeds in their territory, those seeds can’t grow into new trees. Seeds that are carried away, stored for later, and then forgotten can germinate away from their parent tree, the release states. 

Mortelliti and his team studied how animals react to “new” or unfamiliar seeds of warmer-climate trees.

“The way in which seed predators contend with the novel seed or fruit, and the way in which this interaction subsequently unfolds could have dramatic consequences on a plant species’ successful establishment in the new ecosystem,” the researchers wrote. 

Results suggest the interaction between small mammals and novel seeds may have cascading effects on climate‐induced plant range shifts and community composition, according to the researchers. 

Mortelliti conducted the research in Acadia National Park as part of a Second Century Stewardship fellowship from Schoodic Institute, the National Park Service, and the National Park Foundation.

The full Second Century Stewardship news release is online